Highlights: The Trump presidency on April 6 at 7:00 p.m. EDT

FILE PHOTO: U.S. President Donald Trump faces a news conference at the White House in Washington, U.S., February 16, 2017. REUTERS/Kevin Lamarque

(Reuters) - Highlights of the day for U.S. President Donald Trump's administration on Thursday:

U.S. MILITARY OPTIONS IN SYRIA

Facing his biggest crisis since taking office, Trump says "something should happen" with President Bashar al-Assad after a deadly poison gas attack in Syria, as the Pentagon and the White House study military options.

Secretary of State Rex Tillerson spoke by phone with Russian Foreign Minister Sergei Lavrov about a poison gas attack in Syria that the United States blames on the Russia-backed Syrian government, a senior State Department official says.

The Republican head of a congressional inquiry into alleged Russian meddling in the 2016 presidential election says he will temporarily step aside from the probe because he is under investigation for disclosing classified information.

TRUMP MEETS CHINA'S XI

Trump and Chinese President Xi Jinping meet face-to-face for the first time, spending some social time together with their wives before digging into the thorny trade and security issues that bedevil the relationship between the world's two largest economies.

A Chinese fighter plane has been spotted on a Chinese-held island in the South China Sea, the first such sighting in a year and the first since Trump took office, a U.S. think tank reports.

NORTH KOREA'S NUCLEAR PROGRAM

Trump says he will be ready to act unilaterally to address North Korea's nuclear program if China does not step up to help with the matter.

Diplomatic and economic measures taken to rein in North Korea's missile program have not had the desired effect, a senior U.S. military commander says after the North's latest test triggers a flurry of calls among world leaders.

COHN BACKS REVIVING GLASS-STEAGALL

White House economic adviser Gary Cohn says he backs bringing back the Glass-Steagall Act, a Depression-era law that would revamp Wall Street banks by splitting their consumer-lending businesses from their investment arms.

TWITTER PRIVACY LAWSUIT

Twitter Inc files a federal lawsuit to block an order by the U.S. government demanding that it reveal who is behind an account opposed to Trump's tough immigration policies.